Rules for writers, Tenth edition - Diana Hacker, Nancy Sommers 2021

Back up your thesis with persuasive lines of argument
Writing arguments
Academic Reading and Writing

Arguments of any complexity contain lines of argument that, when taken together, might reasonably persuade readers that the thesis has merit. You can think of lines of argument as your reasons. The following, for example, are the main lines of argument that student writer Julia Riew uses in her paper about the role of zoos in saving endangered species (see 7h).

THESIS: CENTRAL CLAIM

When zoos protect animals with compassion and consideration for their needs, they encourage concern for the environment and increase financial support for conservation projects — saving not only endangered species but also the planet and humankind in turn.

SUPPORTING CLAIMS

✵ While some critics believe all zoos are inhumane, zoos can treat animals humanely — keeping animals in custody rather than in captivity — with oversight and regulations.

✵ Zoos protect endangered species by providing safe alternatives to their natural habitats, which may no longer exist.

✵ Although these animals may no longer be able to survive in the wild, zoos help the conservation effort by educating society about the dangers of extinction and humanity’s own hand in causing it.

✵ Zoos also raise money for the conservation effort through sales and donations.

If you sum up your main lines of argument, as Riew did, you will have a rough outline of your essay. In your paper, you will provide evidence for each of these claims.